Oxidative Dehydrogenation of Propane over Ni–Al Mixed Oxides: Effect of the Preparation Methods on the Activity of Surface Ni(II) Species

4Ni–Al layered double hydroxide (LDH) precursors were prepared by the following three methods: constant pH coprecipitation, variable pH coprecipitation and urea hydrolysis. The 4Ni–Al mixed metal oxide (MMO) catalysts were obtained by the calcination of LDH precursors at 600 °C, and their catalytic...

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Bibliographic Details
Published inCatalysis letters Vol. 151; no. 2; pp. 497 - 506
Main Authors Gao, Xiaoxia, Wang, Jiang, Xu, Aiju, Jia, Meilin
Format Journal Article
LanguageEnglish
Published New York Springer US 01.02.2021
Springer
Springer Nature B.V
Subjects
Aluminum
Analysis
Catalysis
Catalysts
Chemistry
Chemistry and Materials Science
Coprecipitation
Dehydrogenation
Electric properties
Electrical conductivity
Electrical resistivity
Hydrolysis
Hydroxides
Industrial Chemistry/Chemical Engineering
Metal oxides
Methods
Mixed oxides
Nickel
Organometallic Chemistry
Physical Chemistry
Precursors
Propane
Propylene
Selectivity
Stability analysis
Surface stability
Urea
Ureas
Heterogeneous catalysis
Alkanes
Deactivation
Oxidative dehydrogenation
Activation energy
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Summary:4Ni–Al layered double hydroxide (LDH) precursors were prepared by the following three methods: constant pH coprecipitation, variable pH coprecipitation and urea hydrolysis. The 4Ni–Al mixed metal oxide (MMO) catalysts were obtained by the calcination of LDH precursors at 600 °C, and their catalytic performances in ODHP from 350 to 550 °C were tested. The 4Ni–Al MMO from the urea hydrolysis method showed a higher and more stable propylene selectivity of ca. 40% with propylene yield of ca.11% at 500 °C, and that from the constant pH coprecipitation method was followed, while oxidative cracking of propane occurred on the 4Ni–Al MMO from the variable pH coprecipitation method. It is considered to be closely related to the dispersion and stability of the surface Ni(II) species through comprehensive analysis of XRD, N 2 -adsorption-desorption, TEM, XPS, H 2 -TPR and In-situ electrical conductivity. The urea hydrolysis method with a low salt concentration, leading to an excellent stability of the surface Ni(II) species at high reaction temperature, should be selected to prepare Ni–Al MMO catalysts for ODHP instead of the traditional variable pH coprecipitation method with a high salt concentration. Graphic Abstract
ISSN:1011-372X
1572-879X
DOI:10.1007/s10562-020-03317-6